Horton

Re: [HACKERS] PATCH: multivariate histograms and MCV lists

Thomas Munro <thomas.munro@enterprisedb.com>

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From: Thomas Munro <thomas.munro@enterprisedb.com>
To: Tomas Vondra <tomas.vondra@2ndquadrant.com>
Cc: Dean Rasheed <dean.a.rasheed@gmail.com>, Bruce Momjian <bruce@momjian.us>, Alvaro Herrera <alvherre@2ndquadrant.com>, Andres Freund <andres@anarazel.de>, Mark Dilger <hornschnorter@gmail.com>, Adrien Nayrat <adrien.nayrat@dalibo.com>, Pg Hackers <pgsql-hackers@postgresql.org>
Date: 2018-11-26T22:29:17Z
Lists: pgsql-hackers 
On Mon, Sep 3, 2018 at 11:17 AM Tomas Vondra
<tomas.vondra@2ndquadrant.com> wrote:
> Attached is an updated version of the patch series, adopting a couple of
> improvements - both for MCV lists and histograms.

Hello Tomas,

FYI, here are a couple of warnings from GCC (I just noticed because I
turned on -Werror on cfbot so your patch turned red):

extended_stats.c: In function ‘statext_clauselist_selectivity’:
extended_stats.c:1227:6: error: ‘other_sel’ may be used uninitialized
in this function [-Werror=maybe-uninitialized]
  sel = mcv_sel + other_sel;
      ^
extended_stats.c:1091:5: note: ‘other_sel’ was declared here
     other_sel,
     ^
extended_stats.c:1227:6: error: ‘mcv_sel’ may be used uninitialized in
this function [-Werror=maybe-uninitialized]
  sel = mcv_sel + other_sel;
      ^
extended_stats.c:1087:5: note: ‘mcv_sel’ was declared here
     mcv_sel,
     ^

-- 
Thomas Munro
http://www.enterprisedb.com

Commits

  1. Convert pre-existing stats_ext tests to new style

  2. Add support for multivariate MCV lists

  3. Improve ANALYZE's strategy for finding MCVs.

  4. Clone extended stats in CREATE TABLE (LIKE INCLUDING ALL)

  5. Try again to fix accumulation of parallel worker instrumentation.

  6. Adjust psql \d query to avoid use of @> operator.

  7. Message style fixes

  8. Add security checks to selectivity estimation functions